<div class="tutorial-nav">
{% assign part = site.data.directory[page.part] %}
{% if part and part.last %}
{% assign last = site.data.directory[part.last] %}
<span class="navitem"><a href="{{site.url}}{{site.baseurl}}{{last.url}}">◀ Part {{part.last}}: {{last.title}}</a> • </span>
{% endif %}
<span class="navitem"><a href="{{site.url}}{{site.baseurl}}">{{site.title}}</a></span>
{% if part and part.next %}
{% assign go = site.data.directory[part.next] %}
<span class="navitem"> • <a href="{{site.url}}{{site.baseurl}}{{go.url}}">Part {{part.next}}: {{go.title}} ▶</a></span>
{% endif %}
</div>
